code: def ctx():
      computing = CSession()
      return Context(
          "guest",
          computing=computing,
          federation=StandaloneFederation(
              computing, "fed", ("guest", 10000), [("host", 9999)]
          ),
      )
  
file_path: FATE/python/fate/test/test_matmul.py
imports: import torch
  from fate.arch.computing.backends.standalone import CSession
  from fate.arch.context import Context
  from fate.arch.federation.backends.standalone import StandaloneFederation
  from fate.arch.tensor import DTensor
  from pytest import fixture
label_desc: Use image node_id 1 for calling a global function with example usage: ctx() and returns: Context